/*
* RapidMiner
*
* Copyright (C) 2001-2008 by Rapid-I and the contributors
*
* Complete list of developers available at our web site:
*
* http://rapid-i.com
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see http://www.gnu.org/licenses/.
*/
package com.rapidminer.operator.similarity.clustermodel;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import com.rapidminer.operator.OperatorException;
import com.rapidminer.operator.learner.clustering.ClusterModel;
import com.rapidminer.operator.learner.clustering.ClusterNode;
/**
* Cluster model similarity based on tree depth.
*
* @author Michael Wurst
* @version $Id: TreeDistance.java,v 1.5 2008/09/12 10:32:26 tobiasmalbrecht Exp $
*/
public class TreeDistance extends MostSpecificCommonNodeSimilarity {
private static final long serialVersionUID = 4442795652362134420L;
private final Map<ClusterNode, Integer> depthMap = new HashMap<ClusterNode, Integer>();
public void init(ClusterModel cm) throws OperatorException {
super.init(cm);
calculateDepth(getClusterModel().getRootNode(), 0);
}
public boolean isDistance() {
return true;
}
public double similarity(String x, String y) {
return -2.0 * getWeightOfNode(getMostSpecificCommonNode(x, y)) + (getWeightOfNode(getNode(x)) + getWeightOfNode(getNode(y)));
}
protected double getWeightOfNode(ClusterNode cn) {
return depthMap.get(cn);
}
private void calculateDepth(ClusterNode cn, int depth) {
depthMap.put(cn, depth);
Iterator it = cn.getSubNodes();
while (it.hasNext())
calculateDepth((ClusterNode) it.next(), depth + 1);
}
}